1. Field of the Technology
The present application relates generally to wireless communication networks, and more particularly to methods and apparatus for reducing undeliverable server-initiated IP traffic to mobile stations in a wireless communication network.
2. Description of the Related Art
Internet Protocol (IP) communication networks were originally implemented in land-line environments. Over the past decade, however, emerging wireless networks have been designed with at least some form of IP protocol support. Wireless networks operating in accordance with General Packet Radio Service (GPRS), for example, have been specified to offer a form of native IP networking. In general, GPRS utilizes a series of data-centric network protocols which operate in conjunction with traditional Global Systems for Mobile Communication (GSM) networks.
Networks like those based on GSM/GPRS utilize proprietary tunneling techniques for creating IP-based addressing mechanisms that work over the top of traditional network infrastructure protocols that are not IP-based. In the case of GSM/GPRS, an IP tunnel is utilized which is referred to as a Packet Data Protocol (PDP) Context. A PDP Context utilizes a tunneling service on behalf of two entities, communicating only using native IP packets. The creation of a PDP Context causes an IP address to be allocated and assigned to a mobile station which is linked to an Access Point Name (APN) or host system. Such proprietary methods of exchanging IP packets create design problems and challenges when the state or status of one of the entities changes.
Since modern wireless networks utilize an IP protocol for data exchange, at least some capabilities associated with sending asynchronous host or server-initiated messages (i.e. “pushing” data) to mobile stations have been limited and compromised. In a wireless environment, there are many reasons why an attempt to communicate with a mobile station might fail. At any given time, a host attempting to initiate a message to a mobile station has very little knowledge of whether the mobile station is in-coverage or out-of-coverage, whether it has been switched off, whether it is still assigned to the same IP address, or whether an IP data packet has been ever delivered. These problems are exacerbated by the fact that wireless networks treat each mobile station as a “client”, which is not well-suited for the returning of status information in host-initiated environments.
Communication failures are generally only communicated between proprietary nodes within the network infrastructure. A protocol referred to as the Internet Control Message Protocol (ICMP) defined by Request For Comments (RFC) 792 by the Internet Engineering Task Force (IETF), for example, provides for the reporting of IP messages that cannot be delivered. In particular, ICMP provides limited feedback to both hosts and mobile stations whenever an actual IP message failure occurs. However, conventional ICMP does not inform a host when the mobile station's state or status changes spontaneously. Such state changes are very common in a wireless environment. For example, a network operator may set timeout values for idle PDP Contexts which may be closed when inactivity timers have expired. Note also that without feedback regarding the termination of a PDP Context, the host often utilizes an incorrect IP address when it attempts to send information to a mobile station. When utilizing dynamic IP address assignment, a previously-assigned IP address may be already reassigned which may result in the wrong mobile station receiving the information from the host.
Accordingly, there is a resulting need for methods and apparatus that overcome the deficiencies of the prior art.